U.S. patent application number 12/978077 was filed with the patent office on 2011-04-28 for image forming device.
This patent application is currently assigned to BROTHER KOGYO KABUSHIKI KAISHA. Invention is credited to Hiroshi IGARASHI.
Application Number | 20110097101 12/978077 |
Document ID | / |
Family ID | 38193278 |
Filed Date | 2011-04-28 |
United States Patent
Application |
20110097101 |
Kind Code |
A1 |
IGARASHI; Hiroshi |
April 28, 2011 |
IMAGE FORMING DEVICE
Abstract
An image-forming device includes a main casing, a process
casing, a photosensitive member, a charger, a first duct member, a
fan, and a duct moving unit. The process casing is accommodated in
the main casing and removably mounted thereon. The process casing
has a casing inlet formed therein. The photosensitive member is
disposed in the process casing. The charger is disposed in the
process casing for charging a photosensitive member. The first duct
member has a duct outlet,. The fan blows air on the charger through
the duct outlet of the first duct member and the casing inlet. The
duct moving unit moves the first duct member between a first
position in which the duct outlet of the first duct member is
adjacent to the casing inlet formed in the process casing, and a
second position in which the duct outlet is separated farther from
the casing inlet than in the first position.
Inventors: |
IGARASHI; Hiroshi;
(Nagoya-shi, JP) |
Assignee: |
BROTHER KOGYO KABUSHIKI
KAISHA
Nagoya-shi
JP
|
Family ID: |
38193278 |
Appl. No.: |
12/978077 |
Filed: |
December 23, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11604254 |
Nov 27, 2006 |
7877037 |
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12978077 |
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Current U.S.
Class: |
399/92 |
Current CPC
Class: |
G03G 21/206
20130101 |
Class at
Publication: |
399/92 |
International
Class: |
G03G 21/20 20060101
G03G021/20 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2005 |
JP |
2005-375591 |
Claims
1-20. (canceled)
21. An image-forming device comprising: a main casing; a process
casing accommodated in the main casing and movably mounted thereon,
the process casing having a plurality of casing inlets formed
therein; a plurality of photosensitive members that is disposed in
the process casing; a plurality of chargers that is disposed in the
process casing for charging the plurality of photosensitive
members, respectively; a plurality of first duct members each
having a duct outlet, the plurality of first duct members being in
one-to-one correspondence with the plurality of casing inlets; a
fan that blows air on each of the plurality of chargers through the
duct outlet of each of the plurality of first duct members and the
corresponding casing inlet; and a duct moving unit that moves the
plurality of first duct members between a first position in which
the plurality of duct outlets is adjacent to the corresponding
casing inlets formed in the process casing, and a second position
in which the plurality of duct outlets is separated farther from
the corresponding casing inlets than in the first position.
22. The image-forming device according to claim 21, wherein each of
the plurality of photosensitive drums is rotatably supported on the
process casing and extends in an axial direction, the process
casing has one side and another side in the axial direction, and
the plurality of the casing inlets is formed on the one side of the
process casing.
23. The image-forming device according to claim 21, wherein the
main casing has a door that is configured to open and close for
allowing the process casing to be mounted on and removed from the
main casing, and the duct moving unit switches the plurality of
first duct members to the first position when the door is closed
and to the second position when the door is opened.
24. The image-forming device according to claim 23, wherein the
duct moving unit comprises an interlocking mechanism that operates
in an interlocking relation the door.
25. The image-forming device according to claim 24, wherein the
interlocking mechanism comprises a coupling member that is
connected to the door, and a cam plate that is connected to the
coupling member and that contacts the plurality of first duct
member.
26. The image-forming device according to claim 21, wherein the
duct moving unit further comprises a plurality of urging members in
one to one correspondence with the plurality of first duct members,
each of the plurality of urging members urging the corresponding
first duct member in a direction to bring each of the plurality of
duct outlets to be positioned near the corresponding casing inlet
formed in the process casing.
27. The image-forming device according to claim 21, further
comprising an electric circuit board that supplies power to the
plurality of chargers; wherein each of the plurality of first duct
members is interposed between the corresponding charger and the
electric circuit board and is formed of a synthetic resin.
28. The image-forming device according to claim 27, wherein the
electric circuit board is disposed in a plane substantially
orthogonal to a direction in which each of the plurality of the
casing inlets opposes the corresponding duct outlet when the
plurality of first duct members is in the first position.
29. The image-forming device according to claim 28, wherein each of
the plurality of first duct members has one end portion and another
end portion, the one end portion having the duct outlet of the
corresponding first duct member, the another end portion having an
air inlet through which air flow created by the fan passes, and
each of the plurality of first duct members is pivotably moved
about the corresponding another end portion.
30. The image-forming device according to claim 29, wherein each of
the plurality of first duct members has a recessed part for
preventing interference between each of the plurality of first duct
members and the electric circuit board when each of the plurality
of first duct members pivots.
31. The image-forming device according to claim 27, wherein the
duct moving unit further comprises a plurality of urging members in
one to one correspondence with the plurality of first duct members,
each of the plurality of urging members urging the corresponding
first duct member in a direction to bring each of the plurality of
duct outlets to be positioned near the corresponding casing inlet
formed in the process casing, each of the plurality of urging
members being disposed inside the corresponding first duct
member.
32. The image-forming device according to claim 21, further
comprising a plurality of packings, each of the plurality of
packings being disposed in at least one of the duct outlet and the
casing inlet corresponding to each of the plurality of chargers to
prevent air from leaking through a gap between the duct outlet and
the casing inlet corresponding to each of the plurality of chargers
when the plurality of first duct member is in the first
position.
33. The image-forming device according to claim 32, wherein the
process casing has a surface near a peripheral edge of each of the
plurality of the casing inlets on the corresponding duct outlet
side, and the plurality of packings is provided in the plurality of
casing inlets, respectively, each of the plurality of packings
having an end face on the corresponding duct outlet side, the end
face being positioned further inside the process casing than the
surface of the process casing.
34. The image-forming device according to claim 32, wherein the
process casing has a surface near a peripheral edge of each of the
plurality of the casing inlets on the corresponding duct outlet
side, and the plurality of packings is provided in the plurality of
casing inlets, respectively, each of the plurality of packings
having an end face on the corresponding duct outlet side, the end
face being in flush with the surface of the process casing.
35. The image-forming device according to claim 21, further
comprising a second duct member that is fixed to the main casing,
wherein each of the plurality of first duct members has an air
inlet in fluid communication with the second duct member, and the
fan blows air into each of the plurality of first duct members
through the corresponding air inlet from the second duct
member.
36. The image-forming device according to claim 35, wherein the
main casing comprises a duct part constituting at least a part of
the second duct member.
37. The image-forming device according to claim 35, wherein each of
the plurality of first duct members has one end portion and another
end portion, the one end portion having the duct outlet of the
corresponding first duct member, the another end portion having the
air inlet of the corresponding first duct member, and each of the
plurality of first duct member is pivotably moved about the
corresponding another end portion.
38. The image-forming device according to claim 21, wherein each of
the plurality of first duct members has one end portion and another
end portion, the one end portion having the duct outlet of the
corresponding first duct member, the another end portion having an
air inlet through which air flow created by the fan passes, and
each of the plurality of first duct members is pivotably moved
about the corresponding another end portion.
39. The image-forming device according to claim 38, wherein each of
the one end portions has a tapered surface that is sloped relative
to a direction in which each of the plurality of duct outlets
opposes the corresponding casing inlet when the plurality of first
duct member is in the first position.
40. The image-forming device according to claim 39, further
comprising a plurality of packings disposed in the plurality of
casing inlets, respectively, to prevent air from leaking through a
gap between each of the plurality of duct outlets and the
corresponding casing inlet when the plurality of first duct member
is in the first position, wherein each of the plurality of taper
surface contacts the corresponding packing when the plurality of
first duct member is in the first position.
41. The image-forming device according to claim 21, further
comprising a driving unit disposed on an opposite side of the
process casing from the plurality of first duct members, the
driving unit driving the plurality of photosensitive members.
42. An image-forming device comprising: a main casing; a process
casing accommodated in the main casing and movably mounted thereon,
the process casing having a plurality of casing inlets formed
therein; a plurality of photosensitive members that is rotatably
supported on the process casing and extends in an axial direction,
the process casing having one side and another side in the axial
direction, the plurality of the casing inlets being formed on the
one side of the process casing; a plurality of chargers that is
disposed in the process casing for charging the plurality of
photosensitive members, respectively; a plurality of duct members
each having a duct outlet, the plurality of first duct members
being in one-to-one correspondence with the plurality of casing
inlets; a fan that blows air on each of the plurality of chargers
through the duct outlet of each of the plurality of duct members
and the corresponding casing inlet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from Japanese Patent
Application No. 2005-375591 filed Dec. 27, 2005. The entire content
of priority application is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to an electrophotographic
image-forming device.
BACKGROUND
[0003] Electrophotographic image-forming devices such as laser
printers and photocopiers well known in the art require a charger
for applying an electric charge to a photosensitive member. If the
charger becomes contaminated with airborne (accumulated) dust
particles or other contaminants around the charger, the capacity of
the charger for charging the photosensitive member may become
insufficient.
[0004] The invention in Japanese Patent Application Publication
2003-287996 includes a fan for actively circulating air around the
charger. This construction prevents the charger from becoming
contaminated by airborne contaminants or contaminants that
accumulate around the charger.
SUMMARY
[0005] Normally the charger is detachably mounted in the
image-forming device and accommodated in a casing of a process
cartridge or the like. The casing housing the charger is removed
from the image-forming device when the charger needs to be repaired
or replaced.
[0006] However, since the fan is disposed in the main frame of the
image-forming device and not in the casing of the process cartridge
or the like housing the charger, a ventilation opening (hereinafter
referred to as a "casing inlet") must be provided in the casing of
the process cartridge or the like for allowing air to pass through
from the main frame side of the image-forming device.
[0007] Air blown by the fan is guided into the casing inlet along a
duct. With this construction, if a duct outlet formed in a part of
the duct facing the casing inlet is in close contact with the
casing inlet, then the casing inlet and duct outlet may rub against
each other when the casing is mounted and removed, causing damage
to both the casing inlet and duct outlet.
[0008] On the other hand, if a gap is formed between the casing
inlet and the duct outlet to prevent the casing inlet and duct
outlet from rubbing against each other when mounting and removing
the casing, air blown by the fan can leak through this gap,
drastically reducing the efficiency of blowing air on the
charger.
[0009] In view of the foregoing, it is an object of the present
invention to provide an image-forming device capable of preventing
the casing inlet and the duct outlet from rubbing against each
other, while preventing a dramatic decrease in efficiency at which
air is blown on the charger.
[0010] To achieve the above and other objects, one aspect of the
invention provides an image-forming device including a main casing,
a process casing, a photosensitive member, a charger, a first duct
member, a fan, and a duct moving unit. The process casing is
accommodated in the main casing and removably mounted thereon. The
process casing has a casing inlet formed therein. The
photosensitive member is disposed in the process casing. The
charger is disposed in the process casing for charging a
photosensitive member. The first duct member has a duct outlet. The
fan blows air on the charger through the duct outlet of the first
duct member and the casing inlet. The duct moving unit moves the
first duct member between a first position in which the duct outlet
of the first duct member is adjacent to the casing inlet formed in
the process casing, and a second position in which the duct outlet
is separated farther from the casing inlet than in the first
position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the drawings:
[0012] FIG. 1 is a side cross-sectional view showing primary
components of a laser printer according to an illustrative aspect
of the invention;
[0013] FIG. 2 is an perspective view of a blast path through which
air is blown toward a charger in the laser printer of FIG. 1;
[0014] FIG. 3 is a side view of a ventilation duct constituting the
blast path according to the illustrative aspect of the
invention;
[0015] FIG. 4 is a top view of the ventilation duct constituting
the ventilation path, a drive mechanism, an electric circuit board,
and photosensitive drums according to the illustrative aspect of
the invention;
[0016] FIG. 5A is a side view illustrating an adjacent state in
which a duct outlet is adjacent to a casing inlet formed in a
casing in the laser printer according to the illustrative aspect of
the invention;
[0017] FIG. 5B is a side view illustrating a separated state in
which the duct outlet is separated from the casing inlet in the
laser printer according to the illustrative aspect of the
invention;
[0018] FIG. 6 is an enlarged perspective view of the casing inlet
in the laser printer according to the illustrative aspect of the
invention;
[0019] FIG. 7 is a side view of the laser printer illustrating the
mounting and removal of the process casing according to the
illustrative aspect of the invention;
[0020] FIGS. 8A-8D are cross-sectional views illustrating the
pivoted state of a movable duct member in the laser printer
according to the illustrative aspect of the invention;
[0021] FIG. 9A is a perspective view showing a variation of a duct
moving mechanism in the laser printer according to the illustrative
aspect of the invention;
[0022] FIG. 9B is a side view showing the adjacent state in which
the duct outlet is adjacent to the casing inlet when using the duct
moving mechanism of FIG. 9A;
[0023] FIG. 9C is a side view illustrating the separated state in
which the duct outlet is separated from the casing inlet when using
the duct moving mechanism of FIG. 9A;
[0024] FIG. 10 is a perspective view showing a variation of the
process casing in the laser printer near the casing inlet;
[0025] FIG. 11 is a perspective view showing another variation of
the process casing in the laser printer near the casing inlet;
[0026] FIG. 12A is an explanatory diagram showing a variation of a
casing inlet in a process casing of the laser printer according to
the illustrative aspect of the invention;
[0027] FIG. 12B is a cross-sectional view showing a variation of a
duct outlet of a horizontal duct part in the laser printer
according to the illustrative aspect of the invention; and
[0028] FIGS. 13A-13D are cross-sectional views showing a variation
of a packing in the laser printer.
DETAILED DESCRIPTION
[0029] An aspect in which the electrophotographic image-forming
device of the present invention is applied to a color laser printer
will be described while referring to the accompanying drawings.
[0030] (First Aspect)
[0031] 1. General Structure of a Laser Printer
[0032] FIG. 1 is a side cross-sectional view showing the primary
components of a laser printer 1. In the following description, the
vertical and front-to-rear directions in FIG. 1 are equated with
the vertical and front-to-rear dimensions of the laser printer
1.
[0033] The laser printer 1 includes a substantially box-shaped
(cube-shaped) main casing 3. A discharge tray 5 is provided on a
top surface of the main casing 3 for receiving paper,
transparencies, or other recording sheets that are discharged from
the main casing 3 after a printing operation.
[0034] The discharge tray 5 includes a sloped surface 5a sloping
down from the top surface of the main casing 3 toward the rear side
thereof. A discharge opening 7 is formed in the main casing 3 on
the rear side of the sloped surface 5a for allowing the recording
sheets to be discharged after printing.
[0035] The main casing 3 includes a main frame 31 accommodating an
image-forming unit 10 and the like described later, and a door 32
provided on the front side of the main frame 31. The door 32 opens
and closes to expose and cover an access opening 31a formed in the
front side of the main frame 31.
[0036] A frame member (not shown) formed of metal, synthetic resin,
or the like is provided inside the main frame 31 of the main casing
3. Image transfer units 70, a fixing unit 80, and the like
described later are detachably mounted in this frame member.
[0037] 2. Detailed Structure of the Laser Printer
[0038] The laser printer 1 also includes the image-forming unit 10,
a feeder unit 20, a conveying belt 30, and discharge rollers 50
disposed inside the main casing 3. The image-forming unit 10 forms
images on a recording sheet S. The feeder unit 20 supplies the
recording sheet S to the image-forming unit 10.
[0039] The conveying belt 30 supports and conveys the recording
sheet S to four image transfer units 70a-70d constituting the
image-forming unit 10. The discharge rollers 50 discharge the
recording sheet S through the discharge opening 7 after the
recording sheet S has passed through the image-forming unit 10 (and
the fixing unit 80).
[0040] 2.1 Feeder Unit
[0041] The feeder unit 20 includes a paper tray 21 housed in a
lowest section of the main casing 3. The paper tray 21 accommodates
a plurality of recording sheets S in a stacked state. A feeding
roller 22 is disposed above the front end of the paper tray 21 for
feeding and conveying the recording sheet S stacked in the paper
tray 21 to the image-forming unit 10. A separating pad 23 is
disposed in a position opposing the feeding roller 22 for applying
a prescribed conveying resistance to the recording sheet S to
ensure that the recording sheets are separated and fed one sheet at
a time. The feeder unit 20 also includes a manual feed tray 26
rotatably supported by a lower end thereof.
[0042] The recording sheet S loaded in the paper tray 21 is fed
along a U-shaped path in the front of the main casing 3 and
conveyed to the image-forming unit 10. The image-forming unit 10 is
positioned substantially in a center of the main casing 3. A
conveying roller 24 is disposed in the curved portion of the
U-shaped path and applies a conveying force to the recording sheet
S for conveying the recording sheet S along the curved path toward
the image-forming unit 10.
[0043] A pressure roller 25 is disposed at a position opposing the
conveying roller 24 for pressing the recording sheet S interposed
between the conveying roller 24 and pressure roller 25 against the
conveying roller 24. A coil spring 25a functions to press the
pressure roller 25 (follow roller) toward the conveying roller
24.
[0044] A registration roller 27 is disposed downstream of the
conveying roller 24 in a sheet conveying direction for correcting
skew in a recording sheet S when contacted by the leading edge of
the recording sheet S conveyed from the conveying roller 24 and for
subsequently conveying the recording sheet S farther toward the
image-forming unit 10. A pressure roller (follow roller) 27a is
disposed in opposition to the registration roller 27. A coil spring
27b presses the pressure roller 27a against the registration roller
27.
[0045] 2.2 Image-Forming Unit
[0046] The image-forming unit 10 includes a scanning unit 60, the
image transfer units 70, and the fixing unit 80.
[0047] The image-forming unit 10 is a direct tandem-type device
capable of printing in color. More specifically, the four image
transfer units 70a-70d are juxtaposed along the conveying direction
of the recording sheet S and correspond to the four colors black,
cyan, magenta, and yellow.
[0048] 2.2.1 Scanning Unit
[0049] The scanning unit 60 is disposed in the upper section of the
main casing 3 and functions to form electrostatic latent images on
the surfaces of photosensitive drums 71 provided in the four image
transfer units 70a-70d. More specifically, the scanning unit 60
includes a laser light source, a polygon mirror, f.theta. lenses,
and reflecting mirrors.
[0050] The laser light source emits laser beams L based on image
data. The laser beams L are deflected by the polygon mirror, pass
through f.theta. lenses, are reflected back in the opposite
direction by reflecting mirrors, and finally are reflected by
another reflecting mirrors downward toward surfaces of the
photosensitive drums 71. The laser beams L irradiate the surfaces
of the photosensitive drums 71 to form electrostatic latent images
thereon.
[0051] 2.2.2 Image Transfer Units (Process Cartridges)
[0052] Since the image transfer units 70a-70d have the same
construction, differing only in the color of toner accommodated
therein, only the structure of the image transfer unit 70d is
described in the following example. Further, the image transfer
units 70a-70d will be referred to collectively as the image
transfer units 70 in the following description.
[0053] The image transfer units 70 are disposed below the scanning
unit 60 in the main casing 3 and are detachably mounted therein.
Each image transfer unit 70 includes the photosensitive drum 71, a
charger 72, a transfer roller 73, a developer cartridge 74 and a
process casing 75. The process casing 75 houses the photosensitive
drum 71, charger 72, and developer cartridge 74.
[0054] Since the four image transfer units 70a-70d are integrally
housed in a single process casing 75 in the aspect, the image
transfer units 70a-70d can be mounted in or removed from the main
frame 31 altogether by moving the process casing 75 relative to the
main frame 31 (main casing 3).
[0055] The photosensitive drum 71 is configured of a cylindrical
main drum body 71a for carrying an image to be transferred onto the
recording sheet S, and a drum shaft 71b for rotatably supporting
the main drum body 71a. The outermost layer of the main drum body
71a is formed of a positive charging photosensitive layer of
polycarbonate or the like. The drum shaft 71b extends along the
longitudinal direction of the main drum body 71a through an axial
center thereof.
[0056] The charger 72 is disposed diagonally above and rearward of
the photosensitive drum 71 and opposes the photosensitive drum 71
at a prescribed distance so as not to contact the same. The charger
72 functions to charge the surface of the photosensitive drum
71.
[0057] The charger 72 of the aspect is a Scorotron type charger and
includes a casing 72a of a square cylindrical shape, and a charging
wire formed of tungsten or the like accommodated in the casing 72a.
The charger 72 produces a corona discharge from the charging wire
in order to form a substantially uniform positive charge over the
surface of the photosensitive drum 71.
[0058] The developer cartridge 74 includes a toner-accommodating
chamber 74a for accommodating toner, a toner supply roller 74b for
supplying toner onto the photosensitive drum 71, a developing
roller 74c, and a thickness-regulating blade 74d.
[0059] Toner accommodated in the toner-accommodating chamber 74a is
supplied toward the developing roller 74c by the rotating toner
supply roller 74b. The developing roller 74c carries this toner on
the surface thereof, while the thickness-regulating blade 74d
adjusts the amount of toner carried on the surface of the
developing roller 74c to a uniform layer of prescribed thickness.
Subsequently, the toner carried on the surface of the developing
roller 74c is supplied to the surface of the photosensitive drum 71
in areas exposed by the scanning unit 60.
[0060] The transfer roller 73 is disposed in opposition to the
photosensitive drum 71 and rotates in association with the rotation
of the photosensitive drum 71. By applying a charge of opposite
polarity (negative polarity in the aspect) from the charge carried
on the photosensitive drum to the surface of the recording sheet
opposite the surface being printed as the recording sheet S passes
the photosensitive drum 71, toner deposited on the surface of the
photosensitive drum 71 is transferred to the printing surface of
the recording sheet S.
[0061] 2.2.3 Fixing Unit
[0062] The fixing unit 80 is disposed downstream of the
photosensitive drum 71 positioned farthest downstream in the
sheet-conveying direction and is detachably mounted in the frame
member described above. The fixing unit 80 functions to melt the
toner transferred onto the recording sheet with heat in order to
fix the toner image to the sheet.
[0063] More specifically, the fixing unit 80 includes a heating
roller 81 disposed on the printing surface side of the
sheet-conveying path, and a pressure roller 82 disposed in
opposition to the heating roller 81 on the opposite side of the
sheet-conveying path. The heating roller 81 applies a conveying
force to the recording sheet S, while heating toner on the surface
of the recording sheet S. The pressure roller 82 functions to press
the recording sheet. S against the heating roller 81.
[0064] A motor or other driving unit (not shown) produces a force
for driving the heating roller 81. This rotational force is
transferred to the pressure roller 82 via the recording sheet S in
contact with the heating roller 81 so that the pressure roller 82
follows the rotation of the heating roller 81.
[0065] 2.2.4 Overview of an Image-Forming Operation
[0066] The following is a description of how the image-forming unit
10 forms an image on the recording sheet S. As the photosensitive
drum 71 rotates, the charger 72 applies a uniform positive polarity
to the surface of the photosensitive drum 71. Subsequently, the
scanning unit 60 irradiates a laser beam onto the surface of the
photosensitive drum 71 in a high-speed scan, thereby forming an
electrostatic latent image on the surface of the photosensitive
drum 71 corresponding to an image to be formed on the recording
sheet.
[0067] Next, positively charged toner carried on the surface of the
developing roller 74c comes into contact with the photosensitive
drum 71 as the developing roller 74c rotates and is supplied to
areas on the surface of the photosensitive drum 71 that were
exposed to the laser beam and, therefore, have a lower potential.
In this way, the latent image on the photosensitive drum 71 is
transformed into a visible image according to a reverse developing
process so that a toner image is carried on the surface of the
photosensitive drum 71.
[0068] Subsequently, the toner image carried on the surface of the
photosensitive drum 71 is transferred onto the recording sheet S by
a transfer bias applied to the transfer roller 73. After the toner
image is transferred, the recording sheet S is conveyed to the
fixing unit 80. The fixing unit 80 applies heat to the recording
sheet S to fix the toner image on the recording sheet S, thereby
completing image formation.
[0069] 2.3 Fan System
[0070] Next, a fan system in the laser printer 1 of the aspect will
be described. FIG. 2 is a perspective view of a blast path for air
blown toward the charger 72. For clarity, a portion of the
image-forming unit 10 has been cut away in FIG. 2. FIG. 3 is a side
view of the ventilation duct constituting the blast path. FIG. 4 is
a top view of the ventilation duct. FIG. 5 is an explanatory
diagram showing operations of a movable duct member 112. FIG. 6 is
an enlarged perspective view of a casing inlet 75a formed in the
process casing 75. FIG. 7 is an explanatory diagram illustrating
the mounting and removing operations of the process casing 75.
[0071] The laser printer 1 of the aspect has both a cooling fan
system and a cleaning fan system. The cooling fan system functions
to cool the image-forming unit 10, fixing unit 80, and the like by
recovering heat emitted therefrom. The cleaning fan system actively
circulates air through the regions around the chargers 72 to reduce
the amount of airborne dust particles and other contaminants around
the chargers 72.
[0072] As shown in FIG. 1, an intake 32a is formed in the door 32
at a position corresponding to the top end of the manual feed tray
26. An exhaust unit 90 is disposed in the main casing 3 on the
opposite side of the process casing 75 (the fixing unit 80 side) of
the intake 32a. The exhaust unit 90 draws air A1 into the main
casing 3 through the intake 32a and discharges the air externally
after the air has passed through the main casing 3. This structure
constitutes the cooling fan system.
[0073] As shown in FIG. 2, the exhaust unit 90 is configured of a
collecting duct 92. The collecting duct 92 houses a discharge fan
91 and includes a plurality of exhaust intakes that open toward the
inside of the main casing 3. Filters are provided in the exhaust
intakes 93 for removing dust and other contaminants.
[0074] In the aspect, an axial-flow fan (see JIS B 0132, No. 1012
and the like) is employed as the discharge fan 91. However, it is
also possible to use a multiblade centrifugal fan (see JIS B 0132,
No. 1004 and the like) such as a turbo fan or sirocco fan, or a
cross-flow fan (see JIS B 0132, No. 1017 and the like), for
example.
[0075] As shown in FIGS. 2 and 3, the cleaning fan system includes
a fan 100 for drawing external air through an intake (not shown) in
the side surface of the main casing 3 (main frame 31) and blowing
the air on the chargers 72, and the ventilation duct 110 for
guiding the air blown by the fan 100 toward the chargers 72.
[0076] As shown in FIG. 2, casing inlets 75a are formed in the
process casing 75. The casing inlet 75a is coupled to the charger
72 (casing 72a) with a duct (not shown). In the aspect, air A2
flowing along the ventilation duct 110 toward the chargers 72 is
guided through the casing inlets 75a into one longitudinal end of
the casings 72a and flows through the casings 72a.
[0077] As shown in FIG. 1, the air is subsequently discharged
toward the photosensitive drum 71 through openings (not shown)
formed in the casing 72a. This discharge of air is substantially
uniform along the longitudinal direction of the drum shaft 71b.
After passing through the openings in the casings 72a, the air
merges with air in the cooling fan system and is similarly drawn by
the exhaust unit 90 and discharged externally.
[0078] While a multiblade centrifugal fan is employed in the aspect
as the fan 100, an axial-flow fan, a cross-flow fan, or the like
may also be used.
[0079] 2.3.1 Structure of the Ventilation Duct 110
[0080] As shown in FIG. 2, the ventilation duct 110 includes
movable duct members 112, a fixed duct member 113 fixed to the main
casing 3 (main frame 31), and a duct moving mechanism 114 for
moving the movable duct members 112. Each of the movable duct
members 112 has a duct outlet 111 facing the corresponding casing
inlet 75a.
[0081] 2.3.1.1 Movable Duct Members
[0082] The movable duct members 112 are molded from electrically
insulating material, such as an ABS resin. When the duct outlet 111
formed in the movable duct member 112 is brought near the casing
inlet 75a, as shown in FIG. 5A, the planes formed in the openings
of the duct outlet 111 and casing inlet 75a are substantially
parallel. Each movable duct member 112 is also configured of a
horizontal duct part 112a extending parallel to an axis L1
orthogonal to the plane in the opening of the duct outlet 111, and
a vertical duct part 112b extending orthogonal to the horizontal
duct part 112a. The main frame 31 is formed with a through-hole
31d. The horizontal duct part 112a penetrates the though-hole
31d.
[0083] Each movable duct member 112 also includes an air inlet 112c
formed in the top end of the vertical duct part 112b, and a
rotational shaft 112d provided near the air inlet 112c. The movable
duct member 112 is connected to the fixed duct member 113 and
capable of pivoting about the rotational shaft 112d.
[0084] The movable duct member 112 is pivotably connected to the
fixed duct member 113 with a portion of the vertical duct part 112b
inserted (fitted) in the fixed duct member 113. A packing 112e
formed of an elastic material such as sponge or rubber is provided
between an outer peripheral surface of the vertical duct part 112b
and an inner peripheral surface of the fixed duct member 113.
[0085] Therefore, even if the dimension of the gap formed between
the outer surface of the vertical duct part 112b and the inner
surface of the fixed duct member 113 changes as the movable duct
member 112 is pivotably moved relative to the fixed duct member
113, the packing 112e is capable of elastically changing shape to
seal this gap.
[0086] A leaf spring 114a formed of a steel spring material is
disposed inside the movable duct member 112 and fixed duct member
113. The leaf spring 114a presses the movable duct member 112 in a
direction that moves the duct outlet 111 to be positioned near the
casing inlet 75a. In the aspect, the duct moving mechanism 114 is
configured of the leaf spring 114a and an interlocking mechanism
described later.
[0087] A tapered surface 112f is formed around the peripheral
surface of the horizontal duct part 112a at the end on the duct
outlet 111 side. The tapered surface 112f slopes relative to the
axis L1, reducing the outer dimension of the horizontal duct part
112a toward the end thereof.
[0088] A recessed part 112g is formed in the vertical duct part
112b on the opposite side from the process casing 75. The recessed
part 112g slopes relative to an axis L2 of the vertical duct part
112b. The recessed part 112g is substantially parallel to a planar
surface 121 of an electric circuit board 120 described later when
the vertical duct part 112b is pivoted toward the side opposite the
process casing 75, as shown in FIG. 5B.
[0089] The recessed part 112g prevents interference between the
movable duct member 112 and the electric circuit board 120 disposed
on the opposite side of the movable duct member 112 from the
process casing 75 when the movable duct member 112 is moved by
pivoting.
[0090] The planar surface 121 of the electric circuit board 120 is
substantially orthogonal to the direction in which the movable duct
member 112 is moved (approximately the horizontal direction in the
aspect). The electric circuit board 120 supplies power (about 8000
V) to the charger 72.
[0091] 2.3.1.2 Fixed Duct Member
[0092] The fixed duct member 113 is molded of an electrically
insulating material such as an ABS resin. As shown in FIGS. 5A and
5B, the portion of the fixed duct member 113 on the process casing
75 side is configured of a duct part 31b provided on the main
casing 3 (main frame 31).
[0093] As shown in FIG. 2, the fixed duct member 113 includes a
distribution duct part 113a having a square cylindrical shape, and
a coupling part 113b that couples with the fan 100. The
distribution duct part 113a extends along the juxtaposed direction
of the four image transfer units 70a-70d for distributing air to
each of the movable duct members 112. The fixed duct member 113 is
fixed to the main frame 31 via the duct part 31b.
[0094] 2.3.1.3 Duct Moving Mechanism
[0095] The duct moving mechanism 114 switches the state of the
movable duct members 112 between an adjacent state (or a first
position, see FIG. 5A) in which the duct outlets 111 are adjacent
to the corresponding casing inlets 75a, and a separated state (or a
second position, see FIG. 5B) in which the duct outlets 111 are
separated farther from the casing inlets 75a than in the adjacent
state.
[0096] The duct moving mechanism 114 is mechanically coupled with
the door 32 so as to operate in association with the opening and
closing of the door 32. The duct moving mechanism 114 moves the
movable duct members 112 adjacent to the process casing 75 when the
door 32 is closed and moves the movable duct members 112 away from
the process casing 75 when the door 32 is opened.
[0097] As shown in FIGS. 2 and 3, the duct moving mechanism 114
includes the leaf spring 114a mentioned above, a cam plate 114b
attached to the main frame 31 in such a way as to be capable of
moving in the front-to-rear direction, and a coupling member 114c
for converting the opening and closing operations of the door 32 to
movement of the cam plate 114b. The interlocking mechanism is
configured of the cam plate 114b and the coupling member 114c.
Through the cooperative operations of the interlocking mechanism
and the leaf spring 114a, the movable duct members 112 can be
switched between the separated state and the adjacent state.
[0098] As shown in FIG. 2, triangular-shaped cams 114d are provided
on the side of the cam plate 114b opposite the process casing 75.
Each of the cams 114d has a sloped surface that gradually moves
farther away from the process casing 75 toward the rear side of the
main frame 31. The movable duct members 112 contact the cams 114d
at contact portions 112h (FIG. 3). When the door 32 is opened, the
cams 114d move forward so that the contact portions 112h of the
movable duct members 112 contact the rear portions of the cams
114d. When the door 32 is closed, the cam plate 114b moves rearward
so that the contact portions 112h contact the front portions of the
cams 114d.
[0099] Hence, when the door 32 is closed, the contact portions 112h
of the movable duct members 112 move toward the process casing 75,
placing the movable duct members 112 in the adjacent state shown in
FIG. 5A. When the door 32 is opened, the contact portions 112h move
toward the side opposite the process casing 75 against an urging
force of the leaf spring 114a, placing the movable duct members 112
in the separated state shown in FIG. 5B.
[0100] 2.3.1.4 Process Casing
[0101] As shown in FIG. 5A, the process casing 75 is mounted on the
main frame 31 by a guiding mechanism 31c. The guiding mechanism 31c
is a guide rail, guide roller, or the like provided on the main
frame 31 that enables the process casing 75 to move in the
front-to-rear direction (horizontally). As shown in FIG. 7, the
process casing 75 and the four image transfer units 70 accommodated
in the process casing 75 can be mounted and removed by opening the
door 32.
[0102] As shown in FIG. 6, packing 76 formed of an elastic material
such as a sponge or rubber material is provided in the casing
inlets 75a of the process casing 75. The packing prevents air from
leaking through gaps between the process casing 75 and the
horizontal duct parts 112a when the movable duct members 112 are in
the adjacent state.
[0103] More specifically, a recessed part 75c is formed in the
casing inlet 75a. The packing 76 is fitted into the recessed part
75c so that an end face 76a of the packing 76 on the duct outlet
111 side is positioned farther inside the process casing 75 than a
surface 75b of the process casing 75 near the peripheral edge of
the casing inlet 75a, or is in flush with the surface 75b.
[0104] Hence, the adjacent state of the aspect in which the duct
outlets 111 are adjacent to the casing inlets 75a indicates a state
in which the duct outlets 111 closely contact the packings 76 to
prevent air from leaking between the duct outlets 111 and casing
inlets 75a.
[0105] As shown in FIG. 4, the ventilation duct 110 and electric
circuit board 120 are disposed on one side of the process casing 75
in the aspect (the lower side in FIG. 4). A drive mechanism 71c for
driving the photosensitive drums 71 is disposed on the opposite
side of the process casing 75 (the top side in FIG. 4).
[0106] 3. Features of the Laser Printer According to the Aspect
[0107] In the aspect, the movable duct member 112 can be switched
between an adjacent state in which the duct outlets 111 are
adjacent to the casing inlets 75a and a separated state in which
the duct outlets 111 are separated from the casing inlets 75a.
Accordingly, it is possible to separate the duct outlets 111 from
the casing inlets 75a when moving the process casing 75 and placing
the duct outlets 111 adjacent to the casing inlets 75a when the
process casing 75 is fixed in the main frame 31.
[0108] By separating the duct outlets 111 from the casing inlets
75a, the casing inlets 75a do not rub against the duct outlets 111
when moving the process casing 75, thereby preventing damage to the
duct outlets 111 and casing inlets 75a caused by movement of the
process casing 75.
[0109] By placing the duct outlets 111 to be positioned near the
casing inlets 75a when the process casing 75 is fixed in the main
frame 31, it is possible to reduce the amount of air that leaks
between the duct outlets 111 and casing inlets 75a. This
construction prevents a considerable decline in efficiency for
blowing air on the chargers 72.
[0110] As described above, the laser printer 1 of the aspect can
prevent a sharp drop in efficiency of blowing air on the chargers
72 and can prevent damage to the duct outlets 111 and casing inlets
75a caused by the casing inlets 75a rubbing against the duct
outlets 111.
[0111] Further, the movable duct members 112 are moved in
association with the opening and closing operations of the door 32.
Closing the door 32 places the movable duct members 112 in the
adjacent state, while opening the door 32 places the movable duct
members 112 in the separated state. When the door 32 is opened to
remove the process casing 75 from the main frame 31, for example,
the duct outlets 111 are separated from the casing inlets 75a in
response to the opening operation of the door 32, thereby
facilitating the operation for removing the process casing 75.
[0112] When the door 32 is closed after the process casing 75 is
mounted in the main frame 31, the duct outlets 111 move adjacent to
the casing inlets 75a in association with this closing operation,
thereby facilitating the mounting operation of the process casing
75.
[0113] Further, since the duct moving mechanism 114 moves
mechanically in association with the opening and closing operations
of the door 32, the movable duct members 112 can be moved in
association with the opening and closing of the door 32 using a
simple construction that requires no electrical actuators, sensors
for detecting the open/closed state of the door 32, and the like.
Therefore, the structure of the aspect suppresses an increase in
manufacturing costs for the laser printer.
[0114] Further, by providing the leaf springs 114a for pressing the
movable duct members 112 in a direction that brings the duct
outlets 111 adjacent to the casing inlets 75a, it is possible to
reliably place the duct outlets 111 adjacent to the casing inlets
75a and press the duct outlets 111 against the casing inlets 75a.
Accordingly, this construction more reliably reduces the amount of
air that leaks between the duct outlets 111 and casing inlets
75a.
[0115] However, since a high voltage of 8000 V is applied to the
charger 72, an insulating member must be provided between the
electric circuit board 120 and charger 72 or between the electric
circuit board 120 and a power feeding unit (not shown) provided in
the charger 72 for supplying power from the electric circuit board
120. The insulating member maintains sufficient clearance distance
and creepage distance in order to avoid unnecessary discharge.
[0116] In the aspect, the electric circuit board 120 is disposed on
the opposite side of the movable duct members 112 from the process
casing 75. Since the movable duct members 112 are formed of a
synthetic resin, the movable duct members 112 serve as an
electrically insulating material disposed between the chargers 72
and electric circuit board 120.
[0117] Therefore, an unnecessary insulating member need not be
provided between the electric circuit board 120 and chargers 72 or
between the electric circuit board 120 and the power feeding unit
provided in the chargers 72. By employing the movable duct members
112 formed of an electrically insulating resin material for
ensuring sufficient clearance distance and creepage distance
between the electric circuit board 120 and chargers 72, measures
for avoiding electric discharge can be more easily taken in a
limited space.
[0118] Since the electric circuit board 120 is substantially plate
shaped, the thickness dimension of the electric circuit board 120
orthogonal to the planar surface 121 is smaller than the dimension
parallel to the planar surface 121. Therefore, by arranging the
electric circuit board 120 so that the planar surface 121 is
substantially vertical, as in the aspect, the smallest dimension,
that is, the thickness dimension of the electric circuit board 120
is substantially aligned with the direction in which the movable
duct members 112 are moved (the horizontal direction). Accordingly,
this construction facilitates the allocation of space for moving
the movable duct members 112.
[0119] Further, this construction does not contribute to an
increase in the size of the laser printer 1. The construction also
prevents damage to the duct outlets 111 and casing inlets 75a
caused by the duct outlets 111 rubbing against the casing inlets
75a, while preventing a dramatic decline in efficiency for blowing
air over the chargers 72.
[0120] However, since the electric circuit board 120 is provided
near the process casing 75, there is a high probability of problems
in allocating space for the leaf springs 114a around the process
casing 75.
[0121] The aspect avoids this problem of allocating space around
the process casing 75 for the leaf springs 114a by providing the
leaf springs 114a in the movable duct members 112. Therefore, the
leaf springs 114a can be easily provided without inviting an
increase in the size of the laser printer 1.
[0122] Naturally, since the leaf springs 114a of the aspect are
formed of a steel spring material or other metal having excellent
creep property, the leaf springs 114a are also electrically
conductive. However, since the leaf springs 114a are provided
inside the movable duct members 112, which are formed of an
electrically insulating synthetic resin material in the aspect,
this construction prevents the occurrence of unnecessary discharge
between the electric circuit board 120 and chargers 72 and the
like.
[0123] Further, the packing 76 is provided in the casing inlet 75a
in the aspect for reliably preventing air from leaking between the
duct outlets 111 and the casing inlets 75a.
[0124] Further, the aspect reliably prevents the duct outlet 111
from rubbing against the packing 76 when the process casing 75
moves by configuring the packing 76 so that the end face 76a on the
duct outlet 111 side is positioned farther inside or is in flush
with the surface 75b around the outer periphery of the casing inlet
75a. Accordingly, this structure prevents damage to the packing 76
when the process casing 75 moves.
[0125] By configuring the ventilation duct. 110 of the movable duct
members 112 and the fixed duct member 113 in the aspect, the
movable duct members 112 can be made smaller than when the entire
ventilation path from the fan 100 to the duct outlets 111 is
configured of the movable duct members 112. Therefore, the movable
duct members 112 can be easily moved using less force.
[0126] Further, by forming part of the fixed duct member 113 in the
aspect with the duct part 31b of the main frame 31, it is possible
to reduce the number of parts required to form the ventilation duct
110, thereby reducing the manufacturing costs of the laser printer
1.
[0127] In the aspect, the movable duct members 112 are moved by
swinging about the air inlet 112c end. Accordingly, the range of
motion of the movable duct member 112 is less than when the entire
movable duct member 112 is moved in a translatory motion, thereby
avoiding a need to increase the size of the laser printer 1.
[0128] FIGS. 8A-8D are side cross-sectional views illustrating the
swinging state of the movable duct member 112. These drawings also
show the structures of the casing inlet 75a and the duct outlet 111
in greater detail. As shown in FIGS. 8A-8D, the movable duct member
112 is swingingly moved about the air inlet 112c end. Accordingly,
when the movable duct member 112 is nearest the casing inlet 75a
(including a state of contact), there is a high possibility that
the end face of the duct outlet 111 is not parallel to the end face
of the casing inlet 75a and that the axis L1 orthogonal to the end
face of the duct outlet 111 is not aligned with an axis L3
orthogonal to the end face of the casing inlet 75a. In other words,
there is a danger that the duct outlet 111 and the casing inlet 75a
will not reliably fit together.
[0129] However, the movable duct member 112 of the aspect has the
tapered surface 112f formed on the duct outlet 111 end for guiding
the duct outlet 111 end of the movable duct member 112 into the
casing inlet 75a.
[0130] For example, if the actual pivoting center of the movable
duct member 112 (the rotational shaft 112d illustrated by a solid
line in the drawings) is shifted lower than the designed pivoting
center (the rotational shaft 112d illustrated by a dotted line), as
shown in FIG. 8A, then the axis L1 of the duct outlet 111 will be
offset from the axis L3 of the casing inlet 75a when the duct
outlet 111 approaches the casing inlet 75a, as shown in FIG. 8B.
Hence, the duct outlet 111 and casing inlet 75a do not reliably fit
together.
[0131] However, since the movable duct member 112 is provided with
the tapered surface 112f in the aspect, the actual pivoting center
of the movable duct member 112 is corrected as the duct outlet 111
is fitted into the casing inlet 75a and is aligned with the
designed pivoting center, as shown in FIGS. 8C and 8D.
[0132] Therefore, the duct outlet 111 can be reliably fitted into
the casing inlet 75a, even when the end face of the duct outlet 111
is not parallel to the end face of the casing inlet 75a and when
the axis L1 of the duct outlet 111 is offset from the axis L3 of
the casing inlet 75a.
[0133] Further, providing the recessed part 112g on the vertical
duct part 112b of the aspect allows the duct outlet 111 to be
separated far enough from the casing inlet 75a, without increasing
the area for moving the movable duct member 112. Hence, this
construction reliably prevents damage to the duct outlet 111 and
casing inlet 75a, without leading to an increase in the size of the
laser printer 1.
[0134] Further, by providing the movable duct members 112 on one
side of the process casing 75 and the drive mechanism 71c on the
other side in the aspect, space can be more easily allocated for
the movable duct members 112 than when providing the drive
mechanism 71c and movable duct members 112 on the same side of the
process casing 75.
[0135] The image-forming device of the present invention is not
limited to the aspect described above. Many modifications and
variations may be made therein without departing from the spirit of
the invention, the scope of which is defined by the attached
claims. For example, the duct moving mechanism 114 in the aspect
described above may be replaced with a duct moving mechanism 214
shown in FIGS. 9A-9C. As shown in the drawings, the duct moving
mechanism 214 is disposed on the opposite side of the movable duct
members 112 from the process casing 75. The duct moving mechanism
214 includes a leaf spring 214a, a cam plate 214b mounted on the
main frame 31 so as to be capable of moving in the front-to-rear
direction, and a coupling member 214c for converting the opening
and closing operations of the door 32 to movement of the cam plate
214b. An interlocking mechanism is configured of the cam plate 214b
and coupling member 214c. Through the cooperative actions of the
interlocking mechanism and the leaf spring 214a, the movable duct
member 112 can be switched between a separated state and an
adjacent state.
[0136] In the aspect, the leaf spring 214a is formed of a steel
member that is disposed inside the movable duct member 112 and the
fixed duct member 113, as shown in FIG. 9B. The leaf spring 214a
urges the movable duct member 112 in a direction that moves the
duct outlet 111 away from the casing inlet 75a.
[0137] As shown in FIG. 9A, triangular-shaped cams 214d are
provided on the process casing 75 side of the cam plate 214b. The
cams 214d have sloped surfaces that slope gradually closer to the
process casing 75 toward the front side of the main frame 31. When
the door 32 is opened, the cam plate 214b moves forward so that the
contact portions 112h of the movable duct members 112 contact the
cam plate 214b, as shown in FIG. 9C. When the door 32 is closed,
the cam plate 214b moves rearward so that the front portion of the
cams 214d contact the contact portions 112h, as shown in FIG.
9B.
[0138] Accordingly, closing the door 32 moves the contact portions
112h of the movable duct members 112 toward the process casing 75,
placing the movable duct members 112 in the adjacent state shown in
FIG. 9B. On the other hand, opening the door 32 moves the contact
portions 112h of the movable duct members 112 away from the process
casing 75 so that the movable duct members 112 are in the separated
state shown in FIG. 9C.
[0139] The surface 75b near the peripheral edge of the casing inlet
75a is a flat surface in flush with regions on the surface of the
process casing 75 farther away from the peripheral edge in the
aspect described above. However, process casings 275 and 375 shown
in FIGS. 10 and 11 are also possible. As shown in FIGS. 10 and 11,
surfaces 275b and 375b near the peripheral edge of casing inlets
275a and 375a protrude farther toward the movable duct member 112
than regions 275d and 375d of the surface farther away from the
peripheral edges of the casing inlets 275a and 375a,
respectively.
[0140] As in the aspect described above, the packing 76 is provided
in each of the casing inlets 275a and 375a at a position farther
inside the process casings 275 and 375 than the surfaces 275b and
375b, respectively, or is in flush with the surfaces 275b and
375b.
[0141] In the aspect described above, the casing inlet 75a is
formed so that the longitudinal dimension is substantially
vertical, and the casing inlet 75a is coupled to the charger 72
(casing 72a) with the duct (not shown). However, as in a process
casing 475 shown in FIG. 12A, a casing inlet 475a may be formed in
the process casing 475 so that the longitudinal dimension slopes to
conform with the slope of the casing 72a and so that the
longitudinal dimension is greater than the vertical cross section
of the casing 72a. As shown in FIG. 12B, a duct outlet 411 of a
horizontal duct part 412a corresponding to the duct outlet 111 of
the horizontal duct part 112a in the above aspect may be formed at
a size and slope corresponding to the size and slope of the casing
inlet 475a so as to be capable of fitting into the casing inlet
475a.
[0142] This construction eliminates the duct required to couple the
casing inlet 75a to the casing 72a of the charger 72 and enables
air circulating through the duct outlet 411 and casing inlet 475a
to be efficiently supplied into the casing 72a.
[0143] It is also possible to form a sloped part 76b on the packing
76 for guiding the duct outlet 111, as shown in FIGS. 13A-13D.
[0144] By providing the sloped part 76b for guiding the duct outlet
111, it is possible to ensure a closer fit between the packing 76
and duct outlet 111. Hence, this construction can further suppress
the leakage of air between the packing 76 and duct outlet 111.
[0145] While the movable duct member 112 is pivotably moved in the
aspect described above, the present invention is not limited to
this type of movement. For example, the movable duct member 112 may
also be shifted in a translatory motion.
[0146] Further, while the movable duct members 112 are moved
mechanically in association with the opening and closing of the
door 32 in the aspect described above, the present invention is not
limited to this movement. For example, movement of the movable duct
members 112 may be controlled electrically using a sensor for
detecting the open/closed state of the door 32 and an electrical
actuator.
[0147] In the aspect described above, the cams 114d are configured
to move all four movable duct members 112 simultaneously. However,
the cams 114d may be configured to move the movable duct members
112 in sequence one at a time, fox example. Such a construction can
reduce the operating force required by the cam plates 114b (door
32).
[0148] Further, while the movable duct members 112 move in
association with the opening and closing operations of the door 32
in the aspect described above, the present invention is not limited
to this construction.
[0149] In the aspect described above, the process casing 75
accommodates other components in addition to the chargers 72, but
the present invention is not limited to this structure.
[0150] While the aspect described above is provided with the leaf
springs 114a or other urging unit, the present invention may be
applied to a structure that omits this urging unit. Further, while
the leaf springs 114a disposed in the movable duct members 112 in
the aspect described above, the leaf springs 114a may also be
disposed outside of the movable duct members 112.
[0151] While the movable duct members 112 in the aspect described
above are formed of a synthetic resin material, the present
invention is not limited to this structure.
[0152] The electric circuit board 120 in the aspect described above
is arranged so that the planar surface 121 is vertical, but the
present invention is not limited to this arrangement.
[0153] Further, while the electric circuit board 120 of the aspect
described above supplies electricity to the chargers 72, the
present invention is not limited to this construction.
[0154] In the aspect described above, the packing 76 is arranged in
each of the casing inlets 75a. However, the present invention may
be applied to structures in which the packing 76 is arranged in
each of the duct outlets 111 or omitted altogether.
[0155] While the drive mechanism 71c is disposed on the opposite
side of the process casing 75 from the movable duct members 112 in
the aspect described above, the drive mechanism 71c and movable
duct members 112 may be provided on the same side of the process
casing 75.
[0156] In the aspect described above, the duct outlets 111 are
configured to fit inside the casing inlets 75a. However, the
present invention may apply to other adjacent states, such as a
state in which the casing inlets 75a and duct outlets 111 butt
against one another or a state in which the casing inlets 75a
protrude toward and fit into the duct outlets 111.
[0157] For the adjacent state in which the casing inlets 75a are
fitted into the duct outlets 111, it is possible to form the
tapered surface 112f on the inner peripheral surface of the movable
duct member 112 at the duct outlet 111 end or to provide a tapered
surface on the outer peripheral surface of the casing inlet
75a.
[0158] In the aspect described above, the present invention is
applied to a direct tandem color printer. However, the present
invention may also be applied to a black and white printer, a
four-cycle color printer, or the like.
[0159] While the invention has been described in detail with
reference to specific aspects thereof, it would be apparent to
those skilled in the art that many modifications and variations may
be made therein without departing from the spirit of the invention,
the scope of which is defined by the attached claims.
* * * * *